Linear motion guide units are conventionally used in any relatively sliding arrangement in diverse fields of machinery such as various industrial robots, semiconductor manufacturing apparatus, precision machines, and so on. Most prior linear motion guide units are in general comprised of a guide rail and a slider that fits over the guide rail for relative movement, the slider being composed of a carriage and end caps, which are joined together with fastening means such as screws and so on.
Meanwhile, linear motion guide units are now known in which there is no need of fastening means such as tightening screws to join a carriage together with forward and aft end caps.
For example in the commonly assigned Japanese Patent Laid-Open No. 2002-295469, there is disclosed a linear motion guide unit in which a slider is made up of a carriage, a pair of end caps positioned on the forward and aft ends of the carriage, one to each end, and a carriage housing to accommodate therein the carriage together with the forward and aft end caps. The carriage housing is made in a rectangular frame having widthwise opposite side panels facing the outward surfaces of the carriage and forward and aft end panels facing outside surfaces of the end caps. On the inward surfaces of the side panels in the carriage housing, there are provided raised portions complementary in contour to recesses in the carriage to fit into their associated recesses. Mutual fit of the raised portions into their associated recesses to keep the end caps within the carriage housing makes it easier to join the carriage and the end caps together with the carriage housing to finish the slider with no use of fastening elements including bolts, screws, and so on, which have been needed in the prior slider assembly.
With the prior linear motion guide unit in which the carriage and a pair of the end caps are installed inside the carriage housing all at once as recited earlier, nevertheless, the assembly operations need several more chores that might give rise to error cumulative in assembly operations.
A linear guide arrangement is disclosed in, for example Japanese patent No. 2936166, in which there is no need for any fastening elements to join a carriage and end caps together. The prior linear guide arrangement has a guide carriage including a guide carriage housing into which a carriage member fits together with forward and aft reversing bodies. In assembled state of the guide carriage, projections of the reversing bodies make engagement with longitudinal grooves cut in the carriage member while strips on the reversing bodies come into snap-engagement with their associated slots cut into end panels of the guide carriage housing. With the prior linear guide arrangement recited earlier, in other words, the combination of the carriage member with the reversing bodies are secured in position inside the guide carriage housing by means of snap-action engagement. Thus, the prior linear guide arrangement has no fastening elements including screws, and so on to join the components together. Upon assembly of the prior linear guide arrangement, the reversing bodies are joined on the forward and aft ends of the carriage member with the projections out of the reversing bodies coming into lying on the upper surface of the carriage member, and then the combination so formed is introduced into the guide carriage housing with the reversing bodies being surrounded along their outward surfaces with the guide carriage housing, and at the same time secured within the guide carriage housing with snap-action engagement. In addition, the prior linear guide arrangement has therein rolling element circuits including return guides in the guide carriage housing and turnaround guides in the reversing bodies.
The prior linear guide arrangement could not still get out of error cumulative in assembly operations to fit the combination of the carriage member with the forward and aft reversing bodies into the guide carriage housing.